Study On The Device Structure And Preparation Process Of Ito-free Semitransparent Organic Solar Cells

Semitransparent Organic Solar Cells（ST-OSCs）have received extensive attention from all walks of life due to their high light transmittance.The continuous development in recent years has brought the photoelectric conversion efficiency of ST-OSCs to 13%,which is sufficient for the commercial application of ST-OSCs in many occasions.At present,most of the high-performance ST-OSCs are prepared based on indium tin oxide（ITO）transparent electrodes,but the ITO electrode preparation process is complicated and the cost is high,so it is not suitable for the commercial development of ST-OSCs.This paper focuses on ST-OSCs transparent electrode materials and device structures,using PM6:Y6 as the optically active layer,and fabricating ITO-Free semitransparent organic solar cells by using composite metal films and conductive polymer films as electrodes.And further developed an all-metal inverted structure ST-OSCs without a cathode interface modification layer,which simplifies the device structure and fabrication process and effectively improves the stability of the device under the premise of achieving higher device performance.Specific research contents include:（1）ITO-Free semitransparent organic solar cells with different device structures were prepared by using composite metal film Au/Ag and conductive polymer film PH1000 as positive electrode or negative electrode.The research results show that the preparation process of PH1000 thin film electrode is difficult and the electrical performance is poor,so it is not suitable for the preparation of high performance ITO-Free semitransparent organic solar cells.However,due to the good stability and electrical properties of the composite metal film electrode,the all-metal inverted semitransparent device using the composite metal film as the transparent electrode shows excellent device performance and application potential.（2）On the basis of the research in the first part,by adjusting the thickness of the organic active layer,it is found that the photocurrent of the device increases significantly with the increase of the thickness of the active layer,but the light transmittance of the device decreases accordingly.Therefore,without affecting the light transmittance of the device,we adopted the strategy of solid additives（PS,PMMA）to improve the photocurrent of the device.The research results show that the solid additive can effectively improve the morphology of the organic active layer and optimize the phase separation of the mixed phase of the acceptor material,thereby improving the separation efficiency of excitons.Finally,the photovoltaic performance of the device can be effectively improved without affecting the AVT of the semitransparent device.（3）By optimizing the electrode structure,using Au/Ag/Ti with low work function as the cathode and Au/Ag as the anode,a semitransparent organic solar cell device based on an all-metal inverted structure without a cathode interface modification layer was prepared.The experimental results show that the work function of the cathode Au/Ag/Ti is lower,which is more matched with the LUMO energy level of the acceptor material Y6,and can form a good ohmic contact.Therefore,the device with Au/Ag/Ti as the cathode can also have good device performance without the cathode interface modification layer,and the semitransparent device without the cathode interface modification layer shows more excellent device stability.The development of the Au/Ag/Ti cathode structure not only simplifies the fabrication process of the device,but also effectively improves the stability of the device in air.Therefore,the Au/Ag/Ti electrode is suitable for the commercial application of ITO-Free ST-OSCs.